''Archaeoistiodactylus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

wukongopterid Wukongopteridae is a group of basal pterosaurs, found in China and the UK. It contains eight species in five genera, all dated to the Middle to Late Jurassic period, The Wukongopteridae were first named by Wang ''et al.'' in 2009, not yet givin ...

pterosaur Pterosaurs are an extinct clade of flying reptiles in the order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 million to 66 million years ago). Pterosaurs are the earli ...

from the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Discovery and naming

''Archaeoistiodactylus'' is known from an incomplete

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

with a partial

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

and

lower jaw In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

s. Catalogued as

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen JPM04-0008, it was recovered from rocks of the

Tiaojishan Formation The Tiaojishan Formation is a geological formation in Hebei and Liaoning, People's Republic of China, dating to the middle-late Jurassic period (Bathonian-Oxfordian (stage), Oxfordian stages). It is known for its Lagerstätte, exceptionally preser ...

in western

Liaoning ) , image_skyline = , image_alt = , image_caption = Clockwise: Mukden Palace in Shenyang, Xinghai Square in Dalian, Dalian coast, Yalu River at Dandong , image_map = Liaoning in China (+all claims hatched).svg , ...

, which date to the

Bathonian In the geologic timescale the Bathonian is an age (geology), age and stage (stratigraphy), stage of the Middle Jurassic. It lasted from approximately 168.2 ±1.2 annum, Ma to around 165.3 ±1.1 Ma (million years ago). The Bathonian Age succeeds ...

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 165.3 ± 1.1 Ma (million years ago) and 161.5 ± 1.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...

stages of the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

period. Apart from the skull, it preserves ribs, parts of the wings, hindlimbs and the pelvis. The neck, tail and feet of the specimen are lacking. ''Archaeoistiodactylus'' was first named and described by

Lü Junchang Lü Junchang (; 1965 – 9 October 2018) was a Chinese palaeontologist and professor at the Institute of Geology, Chinese Academy of Geological Sciences. An expert on Mesozoic reptiles, he described and named dozens of dinosaur and pterosaur taxa ...

and Fucha Xiaohui in

2010 The year saw a multitude of natural and environmental disasters such as the 2010 Haiti earthquake, the Deepwater Horizon oil spill, and the 2010 Chile earthquake. The 2009 swine flu pandemic, swine flu pandemic which began the previous year ...

. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is ''Archaeoistiodactylus linglongtaensis''. The generic name is a combination of the Greek ''archaios'', "ancient", with the name of the genus ''

Istiodactylus ''Istiodactylus'' is a genus of pterosaur that lived during the Early Cretaceous period, about 120 million years ago. The first fossil was discovered on the English Isle of Wight in 1887, and in 1901 became the holotype specimen of a new species ...

'', referring to ''Archaeoistiodactylus'' being presumed to have been an older close relative of the latter. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

refers to the provenance near Linglongta.

Description

The front teeth in the upper jaw of ''Archaeoistiodactylus'' are angled backward. In the hand, the

metacarpal bones In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular bones that form the intermediate part of the hand between the phalanges (fingers) and the carpal bones ( wrist bones), which articulate ...

are short.

Classification

Lü and Fucha assigned ''Archaeoistiodactylus'' to the clade

Breviquartossa Pterosaurs are an extinct clade of flying reptiles in the order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 million to 66 million years ago). Pterosaurs are the earlie ...

and considered it to be more closely related to the istiodactylids than to any other group of pterosaurs; however, they considered it to be more primitive than the Cretaceous istiodactylids and regarded it as an ancestor, rather than member of istiodactylid pterosaurs. David Martill and Steve Etches in 2013 suggested that the holotype specimen might actually be a poorly preserved specimen of ''

Darwinopterus ''Darwinopterus'' (meaning "Darwin's wing") is a genus of pterosaur, discovered in China and named after biologist Charles Darwin. Between 30 and 40 fossil specimens have been identified, all collected from the Tiaojishan Formation, which dates t ...

''. In 2014, Corwin Sullivan and colleagues considered the "distinctive midline tooth in the tip of the rostrum" of the holotype specimen to be a probable valid diagnostic feature of ''A. linglongtaensis''; however, the authors considered it more likely that ''Archaeoistiodactylus'' was a basal

monofenestrata Monofenestrata is a clade of pterosaurs. It includes the pterosaurs in which the nasal and antorbital fenestra (openings/holes) in the skull are merged into a single fenestra. The clade includes the pterodactyloids and their close relatives. C ...

n than an istiodactylid. Later, when included in a phylogenetic analysis, ''Archaeoistiodactylus'' fell in a

polytomy An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree ...

with wukongopterids, providing further support for an affinity with the clade. The 2021 description of ''Kunpengopterus antipollicatus'' followed this classification, but considered ''Archaeoistiodactylus'' to be an undiagnostic wukongopterid.

References

{{Taxonbar, from=Q2407008 Monofenestrata Middle Jurassic pterosaurs of Asia Jurassic China Fossil taxa described in 2010 Taxa named by Lü Junchang Paleontology in Liaoning

Discovery and naming

Description

Classification

See also

References